Bomb sight



June 4, 1946.

J. STEEL BOMBSIGIZIT Filed yar ch 28; 1944 5 Sheets-Sheet 1 lllllHllllllll INVENTOR.

June 4, 1946. J. D. STEEL BOMBSIGHT Filed March 28, 1944 s Shets-Sheet 5 INVENTOR.

flTTOR/VEYS.

Ja D. STEEL June 4, 1946.

BOMBSIGHT Filed March 28 1944 5 Sheets-Sheet 4 BY a a a flITQR/VEKS.

June 4, 1946. V J. D. STEEL 2,401,521

I I BOMBSIGHT Filed March 28, 1944 5 Sheets-Sheet 5 lllllllllll 1 63 Q? 100 M2 u.

IN VEN TOR.

Patented June 4, 1946 UNITED STATES PATENT OFFICE.

BOMB SIGHT John D. Steel, Fort Worth, Tex.

Application March 28, 1944, Serial No. 528,453

9 Claims. 1 This invention aims to provide novel means whereby operators on a test plane may make observations relatively to the dropping of a bomb,

which, having been corrected and passed back to a bombing plane, or to a repositor for information, will enable subsequent bombers to score an effective hit.

A further object of the invention is to supply novel means for so mounting a plurality of sighting devices on the test plane that the necessary data may be assembled readily, corrected quickly; and be available for use on a bombing plane having equipment which is a substantial duplicate of the equipment on the test plane.

A further object ofthe invention is to provide a device of the class described which will be simple in construction and facile in operation.

It is within the province of the disclosure to improve generally and to enhance the utility of devices of that type to which the present invention appertains.

With the above and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, may be made within the scope of what is claimed, without departing from the spirit of the invention.

In the accompanying drawings:

Fig. 1 shows, in front elevation, a device constructed in accordance with the invention;

Fig. 2 isa section on the line 2-2 of Fig. 1;

Fig. 3-is an elevation showing, on an enlarged scale, one of the riders and attendant parts;

Fig. 4 is a sectional view disclosing the mechanism whereby one of the telescopes is actuated;

Fig. 5 is a sectional. view of the structure depicted in Fig. 4, the cutting plane being at right angles to the cutting plane in Fig. 4;

Fig. 6 is a transverse section of the mechanism shown in Figs. 4 and 5;

Fig. 7 is a fragmental view in elevation, disclosing the relation which exists between certain of the contacts;

Fig. 8 is an elevation showing the other of the telescopes and a portion of the mechanism for operating it;

Fig. 9 is: an elevation at right anglesto the" showing of Fig. 8;

Fig. 10 is an elevation disclosing the mechanismsof Figs. 8 and9;

Fig. 11 is an elevation looking toward the left hand side of Fig. 10;

Fig. 12 is a sectional view illustrating the structure depictedin Fig. 11;

Fig. 13 is an elevation showing amodified means for mounting One of the telescopes for compound movement;

Fig. 14 is a side view of the structure illustrated in Fig, 13;

Fig. 15 i a circuit diagram;

Fig. 16 is a diagrammatic showing of a signal mechanism employed to transmit information from an observer at one of the telescopes to the pilot of the aircraft on which the device is mounted.

The device forming the subject matter of this application comprises, as shown best in Figs. 1 and 2, a support I, which is located within the fuselage of an airplane and secured, in depending position, to the upper portion 2 of the fuselage or to some accessible part of the framework of the plane. The support I may be of Various construction, without departing from the spirit of the invention, and its longer dimension extends transversely of the longitudinal axis of the plane whereon it is used. The support I includes parallel, U-shaped end members 3, extended fore and aft of the plane and supplied on their lower portions with upstanding racks 4 (Fig. 2). When the plane is in horizontal flight, the end members 3 are vertically disposed, as shown in Fig, 1.

Fixed to the upper part of the support I are parallel, fore and aft tracks 5, whereon a carriage structure comprising carriages 6 is held at 1 for fore and aft sliding adjustment. The means for adjusting the carriage structure 6-6 fore and aft comprises a thwartship upper shaft 8, mounted to rotate in the carriage structure. Pinions 9 are secured to the shaft 8 and mesh with the racks 4.

. end of the shaft.

The shaft 8 may be rotated b an operator, since a hand crank it or its equivalent is fixed to one The carriages Sand the shaft 8 maintain the pinions 9 in mesh with the racks 4. A fore and aft adjustment of the carriage structure makes the device conveniently accessible to operators, considered relatively to the internal structure of the fuselage.

Hangers l l are mounted to swing fore and aft on the shaft 8, in engagement with the lower parts of the carriages 6. The hangers II are supplied with longitudinal racks I2, and have transverse stops it at their lower ends.

The letter S mark a sighting frame, which is a composite structure. It is sufiicient for present purposes to allege that the sighting frame S includes an upper member i5, which is of inverted U-shape when seen in elevation, as in Fig. 1. In vertical transverse section, the upper member I5 is of inverted trough-shape, as Fig. 2 discloses.

A thwartship lower shaft i5 is disposed parallel to the upper shaft 8 and is mounted. to rotate in the upper member [5 of the sighting frame S. At the ends of the member i5 are disposed riders ll, wherein the lower shaft I6 is journaled, as the dash line showing of Fig. 3 makes manifest. The riders i! receive the hangers or rack bars the pendulum arms, as Fig. 1 shows.

H, and are capable of vertical adjustment upon them.

The lower shaft It forms part of a mechanism for raising and lowering the sighting frame S, and, to that end, pinions I6 are secured to the lower shaft, the pinion extending into the the downward movement of the riders and the sighting frame S.

Rotation may be imparted to the lower shaft 6, for the vertical adjustment of the sighting frame S, by means of a hand crank H3, or its equivalent, on that shaft. In order to avoid retrograde rotation of the shaft l6, and a consequent undesired descent of the frame S, responsive to gravity, a ratchet wheel 26 is secured to the shaft, and is engaged by a springpressed pawl 2|, mounted on one of the riders 1, and including a button 22, by which an operator may release the pawl from the ratchet wheel, at will.

A level vial 23, or equivalent device, is mounted on the upper member I 5 of the sighting frame S, and indicate the condition of the frame relatively to a'horizontal line of flight. The sighting frame S has fore and aft swinging movement on the shaft l6. The sighting frame S includes pendulum arms 24, having weights 25 at their lower ends, the upper ends of the pendulum arms being pivoted'at 26 to the upper member |5 of the sighting frame S, for thwartship swinging movement.

The construction as thus far described enables the sighting frame S to swing fore and aft, and the pendulums 24 can swing thwartships, the weights 25 keeping the pendulums vertical, even though the airplane may not be advancing on an even keel. The frame S may be adjusted upwardly and downwardly, relatively to the floor of the fuselage of the aircraft by operating the crank l9. 1

A pair of transverse, spaced links 21 are pivoted at 28 to the pendulum arms 24, for thwartship movement along with the pendulum arms. The links 21 connect the pendulum arms 24 for simultaneous swinging movement, and the links extend thwartship of the aircraft beyond one of An upright 29 is connected by pivot elements 35 to the laterally projecting portions of the links 21, the axes of the pivot elements being parallel to the axes of the pivot elements 28. To the upper end of the upright 29, av table 3| is secured.

To the table 3| is secured a base plate 32 (Figs. 4, 5 and 6), having at one end a reduced extension 33. A bearing 34 is mounted on the base plate 32 in remote relation to the extension 33, a bracket 35 being mounted on the base plate. in close relation to the extension 33. .A shaft 36 is mounted to rotate in the bearing 34 and in the bracket 35, the shaft carrying a hand crank 31 or the like. The shaft 36 has a threaded portion 38, located at that end of the shaft which is remote from the crank 31.

The threaded portion 38 of theshaft 36 engages a nut 39 pivotally mounted on a lide 45, the slide having reciprocation on a crank arm 4| which is secured to a shaft 42. the shaft being mounted to rotate in the extension 33 of the base plate 32. The shaft 42 carries a sighting devic t or the like.

4 such as a telescope 43, the telescope being pivotally mounted at 44 on an offset arm 45 on the base plate 32. The telescope 43 operate in a single fore and aft plane only, to wit, in a vertical plane parallel to the line of advance of the aircraft. The pendulum 24 and associated parts insure the verticality of that plane, and Figs. 4 and 5 make it evident that the telescope can swing on a single axis only, namely that represented by the shaft 42 and the pivota1 mountillg 44. V

The invention includes a micrometer mechanism, comprising a cylinder 46 secured to the shaft 36 in the vicinity, of the crank 31. The cylinder 45 has micrometer calibrations 41. A straight track bar 48 is fixed on the plate 32 in parallel relation to the axis of rotation of the A micrometer screw 56 is secured to shaft 36. the shaft 36 at the inner end of the cylinder 46. The screws 38 and 56 and the cylinder 46 may be considered as parts of the shaft 36.

Pedestals 5| are secured to the plate 32. Parallel guide rails 52 are mounted in the pedestals 5| and in the bracket 35.

An inverted, U-shaped cursor. 53 (Fig. 6) is mounted for reciprocation on the guide rails 52. A nut 54 forms part of the cursor 53, the screw being threaded into the nut. The nut portion 54 of the cursor 53 carries a pointer 55, ex-

tended parallel to the axis of rotation of the shaft 36, and adapted to cooperate with the calibrations 41 on the cylinder 46.

The cursor 53 has an offset 56 (Figs and '1), carrying an electrical contact 51. A slide 58 is adjustable along the track bar 48 and .is held lightly in adjusted positionsby a set screw 59 The slide 58 is supplied with an electrical contact 60. The electricalcontact 60 is adapted to'be engaged by the electrical contact 51 on the offset 56 of the cursor 53.

A small frame 6| (Fig. 6) is mounted on the plate 32. A brake plunger 62 (Figs. 4 and 15) is mounted for reciprocation in the frame 6|, in a direction at right angles to the axis of rotation of the cylinder 46. At its inner end, the brake plunger 62 is provided with a shoe 63, adapted to engage the cylinder 46. At its outer end, the brake'plunger 62 has a head 64. A compression spring 65 cooperates with the plu'nger'62 and with the frame 6|, to cause the shoe 63 to engage the cylinder 46, unless the shoe is constrained to spaced'relation with respect to the cylinder, as disclosed in Fig. 4. 1

In order to maintain the brake plunger 62 and the shoe 63 in the retracted, position of Fig. 4, a latch 66 is pivotally carried at 61 on the frame 6|.

A retractile spring 68 is connected to the latch with micrometer parts to be described herein- 7 after.

Passing to Figs. 8 to 12, on the table 3| is mounted a plate 12, carrying a bracket 13 (Fig. 11), to which afram 14 is pivoted at 15 for swinging adjustment. The frame 14 has'an offset arm I6 (Fig. 10), like the arm 45 f Fig. 5. The frame I4 carries a micrometer mechanism", like the micrometer mechanism shown in Fig. 4 and hereinbefore described in detail.

Instead of being operated by such a part as the hand crank 31 of Fig. 4; the shaft of the microm eter mechanism I1 is actuated by a flexible shaft I8 (Fig. 10'), connected to a rigid shaft 19, journaled in a bearing 80 on the plate I2, and rotated by a hand crank B I.

A shaft 82, corresponding. to the shaft. 42' of Fig. 4, is mounted torotate in the frame I4.

The screw 83 of the micrometer mechanism .1! corresponds to the screw 38 of Fig. 4 and is oheratively connected withthe shaft 82, which. carries atelescope or sighting device 84, by such. a mechanism as the crank arm M of Fig.4, the slide 40 and the nut 39. The telescope 84 .is pivotally mounted in the arm I6 and has swinging movement with respect. to the frame I4, in a thwartship plane. The telescope 84 is adjusted in. the aforesaid plane, through the instrumentality of the crank 8| of Fig. 10.

A micrometer mechanism85 ismounted on the plate I2 and operates in a direction at right angles to that in. which. the micrometer mechanism 11 operates. The micrometer mechanism 85 is substantially like the micrometer mechanism shown in Fig. 4, aside from the fact that the cursor offset 56 of Fig. 4, the contact 51', the slide 58 and the contact. 68. are omitted.

The screw 86 of the micrometer mechanism 85 is connected to the frame I4 by an arm, slide and nut structure 81, shown. in Figs. 12 and 11, and of the kind hereinbefore described at length in connection with that part of the mechanism which is depicted in Fig. 4. The shaft of the micrometer mechanism 85 (represented by the screw 86), corresponds to the shaft 35 of Fig. 4. andis operated by a flexible shaft 88, connected to a rigid shaft 89, operated by a hand crank 9!] or the like, the shaft 89' being journaled in a bearing 91 on the plate I2. By means of the crank 90 and associated. parts, the frame I4 may be swung on. the pivotal mounting I of Figs. 11 and 12, the telescope 84 receiving thwartship swinging movement.

The structure hereinbefore described and. best shown in Figs; 10, 11 and 12, whereby the telescope 84 is mounted for swinging movement in two planes at right angles to each other, may be varied, without departing from the spirit of the invention; and. in that connection, attention is directed to Figs. 13 and 14, wherein the telescope 84a, which has a compound swinging movement, is designated by the reference character 84a.

The plate I2 of Fig. 10 is supplanted by an outer frame 92 (Fig. 13). within which is located an inner frame 93. Opposed portions of the frame 93 are pivoted at 54 to corresponding portions of the frame 92, the inner frame having movement transversely of' an axis A-B. The telescope 84a is pivoted at 95 tothe frame 92 for movement upon an axis CD, at right angles to the axis A.-B. The structure amounts to a gimbal mounting for the telescope 84a.

The frame 93' receives movement with respect to the axis A-B from a micrometer mechanism 98 on the frame 92 and the telescope receives movement with respect to the axis C--D from a micrometer mechanism 91 on the frame 93. The micrometer mechanisms Stand 9! are of the construction' hereinbefore set forth in connection with the micrometer mechanisms TI and 85 of Fig.10.

Referring to Fig. 15-,thenumeral 48 designates the calibrated cylinder" (Fig. 4) which is. part. of the mechanism for operating the telescope 43 fore and aft, the brake plunger being shown at 62, the latch at 66, and the electro-magnet at I0. As to the telescope 84, the calibrated cylinder which forms part of the mechanism. for swinging that telescope fore and aft is marked by the numeral 99,,the brake plunger being shown at I00, the latch at I01, and the electro-magnet at I02. As to the thwartship movement of the telescope 84, thecalibrated cylinder is shown at I03, the. brake plunger at I04, thelatch' at IE5, and: the electro-magnet at I86. The electric-magnet. I02 is grounded as" indicated at 1 I11. The electromagnet I0 is grounded as'shown at I88, and the electro-magnet IE6 is. grounded at I09.

The electro-magnets I02 and I0 are joined by a conductor H8. Branched oif: from the conductor H0 is a conductor III? joined to the electro-magnet I06. The numeral '2 indicates a source of electrical energy of any preferred sort, grounded at one side, as. shown at H3. From the opposite side of the source H2, a conductor H4 leads to the contact 51 on the cursor 53 of Fig. 4.

A normally open. switch II-5, under the control of an operator, connectsthe conductors Ilfl and H4. The. switch II5 appears. as to superficial structure in Figs. 9 and 10. A conductor I IS extends between the. contact 60' (Figs. 4 and '7) on the slide 58' (which isadjustable along the track bar 48) and an electro-magnet III on the aircraft, the eleotro-magnet being grounded at II8. Any appropriate portion. of' the aircraft supports a release for a bomb I20. The release may include a pivotally mounted radius arm I2 I, having an armature IZIa Which is responsive to the electro-magnet Ill. The bomb release may be-of. any desired nature.

Assuming that the switch II5 of Figs; 9, 10 and 15 is open, it will be understood that when the contact 51 of the cursor 53 engages the contact 8!] on the adjustable slide 58, the electro-ma-gnet III will be energized and will attract the radius arm I2 I, the bomb I25 being released.

' When an operator stationed at the telescopes 8.4 closes the switch I I5, the electro-magnets' I0, I06 and. I02 will be energized, thereby retracting the latches 86, I05 and IDI, the brakeplungers 62, I04 and I00 of Fig. 15 being advanced by the spring 65 of Fig. 4, and similar springs, so that the brake plungers engage, respectively; the cylinders 46, I03 and 99*, the rotation of the shaft 36 of Fig. 4 and the fore and aft' movement of the telescope 43 terminating, the rotation of the cylinders I03 and 99 being terminated in a similar way, and the compound movement of the telescope 84, both fore and aft, and thwartship, coming to an end. It is assumed of course, that the operator will not turn the crank 31 of Fig. 4, or the cranks 90 and BI of Fig. 10, after'the brake pressure is felt; although the brake mechanim. might bestrong enough to resist actuation by the cranks under any reasonable eifort. that the operator might expend upon them. 7

In Fig. 16 there is shown a signal. I22, which is disposed in a position convenient for the pilot of' the aircraft. The numeral I23 indicates an operating means located adjacent to the. telescope 43; There is' an operative connection I24. between the mechanism shown at I23'and the signal I22. The showing of Fig. 16 is purely diagrammatic, the actual construction of thesigna lling mechanism being no" more than a job for a forms part of the shaft 36, the crankarm at Pearl Harbor makes manifest.

mechanic or an electrician. By means of the device indicated in Fig. 16, the observer at the telescope 43 may transmit instructions to the ilot.

D At this point the function and the mechanical operation of various groups of parts will be considered, and then the solution of a specific problem will be discussed.

Referring to Figs. 1 and 2, it will be noted that the frame S and the hangers H are suspended from the thwartship shaft 8, and the frame will maintain a vertical position even though the aircraft is not advancing on a horizontal line 'of flight. Thus there is assured a vertical line which serves as a datum to which angles measured thwartship, or fore and aft, that is, in a vertical plane including the line of advance, may be referred.

Passing to Figs. 4, 5, 6 and7, the operator sets the slide 58 on the bar 48 in accordance with his a judgment. When the shaft 36 is rotated by means of the crank 31, a fore and aft swinging movement is imparted to the telescope 43, through the instrumentality of the screw 38 whiclli and attendant parts, and the shaft 42. r

The cursor 53 is actuated by the screw 50 on the shaft 36 and, ultimately, the contact 51 on the cursor comes into engagement with the contact 60. Referring to'Fig. 15,-the circuit which includes the conductor H4, the conductor Ht and associated parts is energized, and the electro-magnet H1, attracting the radius arm l2l, brings about a dropping of the bomb I20. A reading may be taken at any time by means of the micrometer mechanism which includes the calibrations 41 on the cylinder 46.

Referring to FigsLlO to 12, the telescope 84 is'swung fore and aft when the crank 8| is actuated, and is swung thwartships, when the crank 90 is actuated.

In the practical operation of the device, a plane (which may be referred to conveniently as a test plane) equipped'with the structure hereinbefore described, is flown toward a target, or objective to be bombed. The test plane drops a test bomb, which as to physical characteristics, is a duplicate of the bomb which is dropped later, by another plane, in order to consummate the work of de-' struction, the plane which drops the potent bomb being referred to as the bombing plane.

The testplane accumulates data which are radioed, or transmitted otherwise, backto a following bombing plane. In the data sent back,

errors in the work of the test plane are corrected, and the bombing plane, therefore, is in possession of information which will enable it to drop an explosive bomb with reasonable certainty that the bomb will strike the target, or at least land close enough thereto to fulfill its mission, practically considered.

It is presupposed that the following bombing plane operates under the same conditions that the test plane has encountered, reference being had to such quantities as speed, elevation and weather conditions.

If it is offered as an objection that the operation of the bombingplane, under conditions duplicating those that attended the operation of the test plane, results in increase of risk to the bomber and crew from anti-aircraft fire, it should be noted that such a risk is no more than a hazard of warfare. Moreover, anti-aircraft fire may not be available immediately, as the disaster 8 V The operator at the telescope 43 sets the slide 58 in a position on the graduated track bar 48 dictated by his judgment. The operator at the telescope 43, which swings fore and aft only, points his instrument on the target. If the pilot of the aircraft permits it to get off its course, laterally considered, the operator at the tele scope 43 notifies the pilot by means of the signal mechanismshown in Fig. 16, and the pilot can rectify his course. 1 I I Through the operation of the crank 31 0f Fig. 4, and attendant parts, the person at the telescope 43, swings that telescope in a vertical plane and keeps it on the target, the pilot taking ad'- vantage of the information which he receives from the operator at the telescope 43 and seeing to it that the craft does not sag laterally off her course.

When the person at the telescope 43operates the crank 31, he causes the contact on the cursor- 53 to approach and finally touch the contact 60 of the slide 58 on the track bar 48. Then the circuit which includes the conductors H4 and N6 of Fig. 15 is closed,'the electro-magnet H7. is energized, and the trial bomb'l28 is dropped. Whatever the system of forming the calibrations 41 on the cylinder 48 may be, the reading, in substance, is an angular reading, or in arc, although it need not be expressed in degrees and fractions thereof.

The observer at the telescope 43 continues to hold on the target,- to the end that he my act in the capacity of course-adviser to the pilot. In this connection it should be noted that the slide 58 of Fig. 4 does not serve as an impeding stop for the cursor 53, on-the track bar 48.

Suppose that the observer at the telescope 43 has set the slide 58 at a reading of 1286 on the graduated track bar 48 and he continues to keep the telescope 43 on the target. The operator at the telescope 84 has set his micrometers H and at zero; When the bomb is dropped by engagement between the contacts 51 and 60 of Fig. 4, the observer at the telescope 84 follows the bomb fore and aft, by the micrometer mechanism 17 of Fig. 10, and laterally by the micrometer mechanism 85 of that figure. When the bomb explodes, the observer at the telescope 84 stops the operation of all three micrometers by operating the switch H5 of Figs. 10 and 15, the brake members 62, I04 and I00 of Fig. 15 being applied.

Suppose that the observer at the telescope 84 has obtained a fore and aft reading of 1424 and a thwartship reading of as the bomb strikes. Suppose, also, that at the time the bomb strikes and explodes, the observer at the telescope 43 has a target reading of 1200. Comparing the figures'1424 and 1200, it appears that the observer at the telescope 43 has made a fore and aft error of 224 in the setting of his slide 58. Due to conditions beyond his control, he has made a thwartship error of 110, shown on the micrometer 85;

The correction 224 is applied to the reading 1286, and the test plane has a corrected course reading which may bepassed back to the bombing plane. The slide 58 and the micrometer mechanism 85 of the bombing plane then may be set properly, and the active bomb will be so dropped as to hit the target. The bombing plane preferably does not have the'fore and aft telescope 43 and attendant parts, since that telescope is useful chiefly to collect data and to keep the collected.

test plane on its course whilst the data are being since the slide is held but lightly The sighting frame S may be referred to as a carrier, and the carrier is so mounted on the upper portion 2 of the aircraft that the carrier will define a vertical line of reference. The telescope 43 is a first sighting device. The telescope 84 is a second sighting device. Various micrometer mechanisms, such as that shown in Fig. 4, constitute actuating means. In Fig. 15, a bomb release is shown at l2l and the electrical connections constitute means for operating the release. The operating means, as above described, comprises normally inactive parts, such as the contacts 51 and 60 of Fig. 4. Such parts are incorporated in the actuating mechanism for the first sighting device 43, that is, the mechanism shown in Fig. 4, and they are incorporated, in duplicate, in the mechanism shown at 11 in Fig. 10, whereby fore and aft swinging movement is imparted to the telescope 84. The aforesaid parts 51 and (iii coact under the impulse of the actuating mechanism, for instance, that shown in Fig. 4, to bring about bomb release.

What is claimed is:

l. A bombsight comprising a carrier, means for pivotally mounting the upper portion of the carrier on an aircraft whereby the carrier will define a vertical line of reference, a sighting device, means for mounting the sighting device on the carrier for swinging movement in a Vertical, fore and aft plane, and in a vertical, thwartship plane, an actuating mechanism operatively connected to the sighting device, to swing it in a fore and aft plane, and an actuating mechanism operatively connected to the device, to swing it in a thwartship plane and means for mounting the carrier for raising and lowerin with respect to the aircraft whereon it is mounted.

2. A bombsight comprising a sighting frame, means for suspending the sighting frame from an aircraft for fore and aft swinging movement, the sighting frame including a pendulum having thwartship swinging movement, a sighting device, means for mounting the device on the frame for swinging movement in a vertical fore and aft plane, and in a vertical, thwartship plane, mechanism operatively connected to the sighting device, to swing it in a fore and aft plane, and mechanism operatively connected to the sighting device, to swing it in a thwartship plane.

3. A bombsight constructed as set forth in claim 1, in combination with means for imparting fore and aft adjustment to the carrier, at the will of an operator.

4. A bombsight constructed as set forth in claim 1, in combination with means for mounting the carrier for raising and lowering with respect to the aircraft whereon it is mounted, and means for mounting the carrier for fore and aft movement.

5. A bombsight comprising a support, means for mounting the support in elevated position on an aircraft, the support having a fore and aft rack, a carriage structure, means for mounting the carriage structure for fore and aft sliding movement on the support, a first shaft journaled in the carriage structure, a pinion carried by the first shaft and meshing with the rack, means for rotating the first shaft, hangers suspended from the first shaft for fore and aft swinging movement and provided with substantially vertical racks, riders mounted for vertical sliding movement on the hangers, a second shaft disposed parallel to the first shaft and journaled in the riders, means for rotating the second shaft, a.

10 member mounted to swing fore and aft on the second shaft, pendulums suspended from said member for thwartship swinging movement, a link pivoted to the hangers, and sighting means mounted on the link.

6. A bombsight comprising a support, means for mounting the support in elevated position on an aircraft, a carriage structure, means for mounting the carriage structure for fore and aft sliding movement on the support, means under the control of an operator for imparting fore and aft sliding movement to the carriage structure. depending hangers, substantially vertical racks on the hangers, means for mounting the hangers on the carriage structure for fore and aft swinging movement, riders mounted for vertical sliding movement on the hangers, a thwartship shaft journaled in the riders, pinions on the shaft and meshing with the racks, means for rotating the shaft, a member mounted to swing fore and aft on the shaft, pendulums suspended from said member for thwartship swinging movement, a link pivoted to the hangers, and sighting means mounted on the link.

7. A bombsight comprising a support, means for mounting the support in elevated position on an aircraft, the support having a fore and aft rack, a carriage structure, means for mounting the carriage structure for fore and aft sliding movement on the support, a shaft journaled on the carriage structure, a pinion carried by the first shaft and meshing with the rack, means for rotating the shaft, hangers suspended from the shaft for fore and aft swinging movement, riders mounted for vertical sliding movement on the hangers, means under the control of an operator for imparting vertical sliding movement to the riders, a member mounted on said means for fore and aft swinging movement, pendulums suspended from said member for thwartship swinging movement, a link pivoted to the hangers, and sighting means mounted on the link.

8. A bombsight comprising a support, means for mounting the support in elevated position on an aircraft, a carriage structure, means for mounting the carriage structure for fore and aft sliding movement on the support, means under the control of an operator for imparting fore and aft slidin movement to the carriage structure, depending hangers, means for mounting the hangers on the carriage structure for fore and aft swinging movement, riders mounted for vertical sliding movement on the hangers, means under the control of an operator for imparting vertical sliding movement to the riders, a member mounted on said means for fore and aft swinging movement, pendulums suspended from said members for thwartship swinging movement, a link pivoted to the hangers, and sighting means mounted on the link.

9. A bombsight comprising depending hangers, means for mounting the upper portions of the hangers on an aircraft for fore and aft swinging movement, a frame, means for mounting the frame on the hangers for vertical adjustment at the will of an operator, the frame including pendulums having thwartship swinging movement, parallel links pivoted to the pendulums and disposed transversely thereof, an. upright pivotally connected to the links and maintained thereby in parallel relation to the pendulums, and sighting means carried by the upright.

JOHN D. STEEL. 

